East Antarctica Appeared To Be Missing Earthquakes - And Now We Finally Know Why

Pictured here is the Matusevich Glacier, flowing toward the coast of East Antarctica, seen in September 2010. GSFC/NASA Goddard

Although we’re learning plenty by the day, there’s still a lot we don’t know about Antarctica. Lest we forget, it’s an enormous continental landmass covered and surrounded by ice that’s responding unevenly to the warming world. We’ve also, by the way, just this year had a detailed peek beneath the ice around the South Pole.

Fortunately, thanks to a suite of instrumentation implanted into the East Antarctic, we now know that East Antarctica isn’t bizarrely aseismic – as the data had suggested – but instead full of quakes and shakes.

A study dating back to 1986 explains that the first earthquake in the interior of the Antarctic continent was detected in Dronning Maud Land, which took place in 1982. In the years proceeding, several more were detected in various locations, and some were large enough to be located by the US National Earthquake Information Service.

It seemed odd, though, that so few quakes were being registered there, but no one could be quite sure why. As a new Nature Geosciences study elucidates, this is largely down to the fact that the underlying geology is somewhat ambiguous.

“Buried deep beneath the Antarctic polar ice sheet, the geological structure and tectonic activity of East Antarctica have long remained unknown,” the authors, led by Drexel University, explain.

Saying that, they note that the “apparent lack of tectonic seismicity” was anomalous relative to the interiors of other continents, which are rife with fault lines, mountain ranges, basins, and more, all undergoing tectonic stresses and strains. Why isn’t there more seismicity then?

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One small part of the new array. Drexel University

This curious lack of shakes has been attributed to plenty of things in the past, including – but not limited to – the incredibly slow propagation of the tectonic plates here, or the massive overburden of ice preventing much movement. Still, it seemed odd to many. Was there something weird going on here?

Attempting to solve this mystery, the team – which also included Washington University and Pennsylvania State University – took to the icy realm to find out more.

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